Impact of high-k gate stack material with metal gates on LF noise in n- and p-MOSFETs

Abstract

The aim of this paper is to study the 1/f noise performance of n- and p-channel MOSFETs with different Hf-based gate stacks, deposited by MOCVD and using metal (PVD TaN) as a gate material. The drain current dependence is different for n- and p- channel devices over the noise spectra, showing different noise origin mechanisms – mobility fluctuations for pMOS and number fluctuations for nMOS. Asymmetric trap density distributions with energy between n- and pMOS have been observed which is a possible reason for the observed lower noise magnitude in pMOS devices. A fair comparison using Hooge’s parameter and trap densities as figures of merit shows weak correlation on the Hf-composition, allowing a large window for gate stack processing of devices.